Magneto



-W. E. SCHWARZMANN.

MAGNETO.

APPLICATION HLED on. 12. ma.

1 ,344,723, Patenwd June 29, 1920.

of the ma UNITED STATES PATENT OFFICE.

WOLFGANG ERNEST SCHWARZMANN, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR,IBY MESNE ASSIGNMENTS, TO AMERICAN BOSCH MAGNETO COBIORATION, OF NEWYORK, N. Y., A. CORPORATION OF NEW YORK.

MAGNET).

Specification of Iietters ratent. Patented J une 29, 1920.

Application filed October 1 2, 1918. Serial No. 257,841.

To all wk mit may concern: or other type, having many cylinders, or

Be it known that I, Wows-mo E. rotating at high speed, or both, whereinthe SCHWARZMANN, a citizen of the United power strokes occur atirregular intervals. States residing at 51 Bellclaire avenue, Inaccordance with my invention, I provide Long Meadow, Spririgfield, inthe countypf a magneto having an unsymmetrical ma Hampden, State ofassachusetts, have innetic circuit, that is one in which the traiing'tips of the field and armature poles are disposed at irregularintervals around a circle, or a magneto havi the field and armaturepoles and the mem ers of the sleeve so constructed and arrangedrelatively to each otherthat upon rotation of the sleeve, the trailingtips of the sleeve members leave the trailing tips of the field andarmature poles at the unequally spaced intervals corres ending to theirregular ignition desired. referably, I do this by providingunsymmetrical field poles, or'unsymmetrical arma ture poles, or both,the members of the sleeve being coordinated with those poles to breakaway therefrom at the irregular intervals, and thereby alter themagnetic flux in the generating winding. By altering the electricalcircuit of the generating winding at substantially those irregularintervals, as, for instance, by a mechanical interrupter on an electromagnetic sparkplug, ignition volta s are generated at those intervals;and y arranging the distributer to then connect the generating windingto the suc cessive spark-plugs, ignition sparks are produced in theengine cylinders at the firing periods desired.

In the accompanying drawings illustrat ing my invention in application,as an example, to a high tension magneto havinga bipolar field andarmature and a sleeve for generating four ignition voltages per rotationfor a 12-cylinder, -cycle engine with its cylinders on a 45 V,

Figure 1 represents a longitudinal cross section of one embodiment of myinvention;

Fig. 2 is a transverse section of the magneto of Fig. 1;

Fig. 3 is a wiring diagram showing the mechanical interrupter and thedistributer associated with the magneto;

Fi 4 to 7 are diagrams showing the position of the rotatable sleeve'atfour successive ignition iper-iods; and

Fig. 8 represents a modified construction.

Referring particularly to Figs. 1 to 7 the vented certain new and usefulImprovements in Magnet/us; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as willeiiable others skilled in the art to-which it appertainsto makeand usethe same.

[he present invention relates to magnetos of the sleeve type fori itingcombustible mixtures in internal com ustion engines,the sleeve havingmembers of magnetic material and being rotated in the air gap betweenthe armature and field poles of the magneto to alter or reverse the fluxflowing from the field magnet through the generating winding at theintervals of ignition.

Airplane engines are now made with 8 to 18 cylinders in V or fanarrangement with the two or three planes of cylinders spaced apartdifl'erently than the usual angle, which, in the case of two planes, is90 for 8 cylinders, 60 for 12 cylinders, or, in general, is equal to 360or 720 divided by the number of cylinders. Other airplane engines havetheir cylinders arranged in one or two circular series. In some of suchengines, the departure from the usual spacing necessitates ignition atirregular intervals, that is at unequal angles of rotation; forinstance, an engine at present in use has 12 cylinders arranged in twoplanes on a 45 V, and requires ignition at 45,'75, 45, and so on,inasmuch as the explosions occur in the cylinders of the two planesalternately.

Furthermore, the lar e number of cylinders, or the high spec of rotationo the engine, or both, necessitate such excessively rapid sparkin thatwhen a magneto is used it should pro uce more than the two sparks perrotation generated by an ordinary bipolar magneto, because the speed ofrotation eto would otherwise be too high. The ob ect of my inventionisto provide a magneto which meets the foregoing requirements, and is,therefore, intended especially for association with an internalcombustion engine of the V, fan, circularr magnetic circuit of themagneto includes a stationary permanent magnet l with poles 2 and 3, andan armature core with oles 4 and 5 connected by the cross bar 6. ecorresponding tips of the W" field poles, and also of the two armaturepoles, are the rammatically opposite. the armature poles eing disposedin the field interpolar spaces so that the trailing tips of one aresubstantially in radial line with the leading tips of the other.Furthermore, each field interpolar space. and thus each armature polarspan, is substantially (57.5" in an ular extent, and each field polarspan, and thus each armature intcrpolar space, is substantially 112.5.In general, these an ular extents are sub stantially tqlltll to theirregular intervals of firing of the engine multiplied by the ratio ofthe magneto speed to the engine crank shaft speed, or, in this case, to45 times L}. and 75 times 12;. respectively.

The armature poles 4, 5 are abbreviated on opposite sides of the centerline A.-.\ of the crossbar (5; aml the angular extents of the portionsof those poles as well as of the field pole 2. 3. are dissimilar inadjacent quadrants with respect. t. that line, but similar in alternatequadrants.

The magnetic sleeve has two iron |nem hers S magnetically sepa'atcd fiomeach other and held in position by the brass end plates 9. The membershave a like span of about 72.5". and are arranged to simultaneouslybridge the field interpolar spaces, and to later simultaneously leavethe trailing tips of the armature poles.

The shafts Ill. 11 of the sleeve arc sup ported in ball bearings 12, 13carried by the members-14. 15 which are secured to the base plate of themagneto and are therefore rigid with respect to the poles of the fieldmagnet 1. The shafts 16 and 17 of the armature are mounted in ballbearings 18, 19 carried in enlarged recesses of the two shafts of thesleeve. The shaft 16 extends through and bcvond the hollow shaft ll) andcarries a collar 20 fast with it and with a stationary member 21 tosecure the armature against rotation. The sleeve is rotated in itsbearings by the gear :22. which is of proper size to be driven from thecrank shaft of the engine at the required speed ratio. As showndiagrammatically in Fig. 3. one terminal of the primary turns 23 of thegenerating winding is connected to one terminal of the secondar turns2-l of the generating winding. and thence to the stationary insulatedelement an of the mechanical interrupter. The other terminal of theprimary turns is "grounded. while the other terminal of the secondaryturns is connected to the rotatable brush 26 of the distributer. whichis driven by the gears 31 34, at the required speed of rotation. inthlsrcase at one-third the speed of the sleeve. he cam member of the mechanical interrupter is fast with the sleeve and has four cams 2T spacedapart 67.5", 112.5, (i7.5, and 112.5", to deflect the grounded movableelement 28 of the me chanical interrupter and thereby interrupt theprimary turns of the generating wind ing at the irregular intervals ofignition. At those intervals the distribnter brush 26 engages thesparkplug distributing contacts 29, which are correspondinglyirregularly spaced to conduct the ignition currents from the generatingwinding to the insulated terminals of the spark-plugs 30 in the enginecylinders.

The position of the sleeve members at the four irregular intervals ofignition are illustrated (liagrammatically in Figs. 4- to T for theembodiment of the magneto shown in Figs. 1 to 3. In Fig. 4, the trailingtips of the members 8 of the sleeve are leaving the trailing tips of thefield poles 2, 3. thereby reducing the magnetic flux flowing through thecross bar (5. and therefore in the generating winding mounted thereon.Shortly after that moment. the magnetic flux is established through theaimatnrc in the opposite direction. the finx thus being reversed in asmall angle of rotation. .;\t (37.5 later in the rotation. the trailingtips of the sleeve members 5 leave the trailing tips of the armaturepoles l. 5. as shown in Fig. 5. the flux previously flowing through thearmature being reduced. .\t about 4-0" after this moment, the magneticllnx is established in the opposite direction through the armature andthus completes the re vcrsal of the flux therein, the leading tips ofthe sleeve members then being opposite the leading tips of the armaturepoles. At 1112.5 after the second point of ignition. or 180 after thefirst. the trailing tips of the sleeve members it again leave thetrailing tips of the field poles 2. 3. as shown in Fig. (i; and at(37.5" later. or 180 from the second period of ignition. those lipsleave the trailing tips of the armature polcs. as shown in Fig. T. Ateach of these ignition periods, \'i'/.., at 1. (37.5", 180 and 247.5"from the position of the sleeve shown in Fig. 4. the mechanicalinterrupter opens the circuit of the primary turns and the distributerbrush engages the spark plug distributing contact to conduct theignition current produced in the generating winding to the spark plugconnected thereto.

In the modification in Fig. 8, the field poles 31 are symmetrical.instead of unsymmetrical, and each .sleeve member 32 base. span. ofabout 90, which is slightly greater than the field 'interpolarspace. Theelfect of these changes is that, whereas the reversal of the magneticflux in the armature when the sleeve members bridge the field interpohirspaces occurs'in substantially the same angleof rotation as before therenet having poles versal when the sleeve members bridge the armatureinterpolar spaces occurs more rapidly than before. In bothmodifications, but particularly in the latter one, the successiveignition voltages are sufliciently alike for practical purposesthroughout the ordinary range of speed of the en ine with wluch thesemagnetos are inten ed to be associated.

It is to be understood, of course, that various other forms of field andarmature poles may be used, and that the sleeve members may also haveother forms in coordination with the poles. Such modifications areobviously within my invention which embodies an unsymmetrical magneticcircuit, or one in which the trailin tips of the sleeve members leavethe trai ing ti 5 of the field and armature poles to give the irregularintervals of ignition required by an engine of the kind hereinbeforereferred to; the mechanical interrupter altering the circuit of thegenerating winding at said intervals.

Having thus described my invention, what' I claim is:-

1. In a magneto for producing i currents at irregular intervals, a el anarmature having poles, a sleeve rotatable in the air ap between thefield and armature has and avin magnetic members magneticall separatefrom each other, the poles and't sleeve members bein so constructed andarranged that the traili 0 tips of the sleeve leave the trailing tips 0the poles at irregular intervals, a generatin winding, and meansforraltermg the circuit of the generating winding at substantially saidintervals.

2. In a magneto for producing currents at irregular intervals, an unsymmetrical magnetic circuit, a generating magwinding, a magnetic sleeverotatable in the air gap of said magneticcircuit' to alter the magneticflux in the 'enerating winding at the irregular interva s determined bythe unsymmetrical magnetic circuit, and means for altering theelectrical circuit of the generating winding at said intervals.

3. In a magneto for producing ignition currents at irregular intervals,antunsg m eld metrical magnetic circuit including a magnet having polesand an armature having poles, a generating windin on the armature, amagnetic sleeve rotatab e in the air gap between the field and armaturepoles to alter the magnetic flux in the eneratin winding at theirregular intervals etermine by the unsymmetrical magnetic circuit, and'means for altering the electrical circuit of the generating winding atsaid intervals.

4. In a magneto for producing ignition currents at irregular intervals,an uns mnu-tricul magnetic circuit including a eld magnet having polesand an armature havthe generating 5. In a magneto for producingignition,

mined b ition in the ignition ing unsymmetrical poles, a generatingwind: ing, a magnetic sleeve rotatable in the air between the field andarmature poles, to alter the magnetic flux in the generating windin atthe irregular'intervals determined the unsymmetricahmagnetic circuit, anmeansgforaltering the circuit of windingat said intervals.

currents at irre metrical magnetic circuit including a magnet'havingunsymmetrical poles and an armature having oles, a generating winding,a" magnetic s eeve rotatable in the air gap between the field andarmature poles to alter the magnetic flux in the generating winding atthe irregular intervals deterthe unsymmetrical magnetic cirmeans foraltering the circuit of at said intervals.

lar intervals, an runs cuit, an the generating winding 6. In a'magnetofor currents at irre lar intervals, an uns mmetrical magneticunsymmetrical poles, a

generating winding, tatable in the air ga armature poles to a generatingwindin interva 5 determined by t e unsymmetrical magnetic circuit, andmeans for altering the circuit of the generating winding at saidintervals.

7. In a magneto for producin ignition currents at irregular intervals, afield magnet having poles, an armature having poles and a connectingcross bar, the angu ar extent of the portions of the field poles and ofthe armature poles being dissimilar in adjacent uadrants-with respect tothe cenher line 0? the cross bar, a magnetic sleeve rotatable in the airgap between the field and armature poles, and means f or alter ing thecircuit of the generating winding at irregular intervals.

8. In a magneto for producin ignition currents at irregular intervals, afie d magnet having poles, an armature having poles and a connectm crossbar, a generating winding, the angu ar-extent of the portions of thefield poles and of the armature poles being dissimilar in adjacentquadrants with respect to the center line of the cross bar, and beingsimilar in alternate uadrants, a magnetic sleeve rotatable in t e airgap between the field and armature oles, and means for altering thecircuit 0 the generating winding at recurring irregular intervals.

' 9. In a magneto for producing ignition currents at irregularintervals, :1 field magnet having poles, an armature having polesabbreviated on opposite sides of the connecting cross bar therefor, amagnetic sleeve r0- tatable in the air gap between the armature tor the-magnetic flux at the irregular producing ignition between the field andeld circuit oom rising a eld magnet having unsymmetrica poles and an andfield poles, a generatingwinding, and means for altering the circuit ofthe generating winding; t irregular intervals.

10. In a m new for producin ignition currents at irr ular intervals, a'eld magnot having poles, an armature having poles with interpolar'spaces different from the field interpolar spaces, a magnetic sleeverotatable in the air gap between the field and armature 'poles, ageneratin 1 winding, and means for altering the circuit of thegenerating winding at irregular intervals substantially ual to theinterpolar spaces of thefield an armature. h

11. In a magneto for producing ignition currentsat irregular intervals,a field magnet having unsymmetrical poles, an armaliiire havingainsymmetrical oles with their tips substantial] in radial lme withrespective tips of the eld poles. a magnetic sleeve rotatable in the airgap between the armature and fie poles, a generating windin and means,or altering the circuit of the generating winding at irregularintervals.

12. In a magneto for producing ignition currents at irregular intervals.an unsymmetrical magnetic circuit including a field magnet having polesand an armature having poles, a magnetic sleeve rotatable in the air'gap between the field and armature poles and comprising magnetically-separated magnetic members each having a span substantially equal tothe field interpola r space, a generating winding, and means foraltering the circuit of the generating winding at the irregularintervals determined by the unsymmetrical magnetic circuit.

13. In a magiieto for producing ignition currents at irregularintervals, a field magnet having unsymmetrical poles, an armature havingunsymmetrical poles. a magnetic sleeve rotatable in the air gap betweenthe field and armature poles, a generating winding, and means foraltering the circuit of the generating winding at irregular intervals,each of the field inter-polar spaces being substantially equal to one ofthe irregular intervals and each of thc :llllHlLHl'L' lll terpolarspaces being substantially equal to the ad'accnt one of lhc irrcgularinlcrvals.

14. n a magncto for producing ignition currents at irregular intervals.a licld mag not having poles diilc rcnl in span from its intcrpolarspace. an armature having poles different in span from its intcrpolarspace, a magnetic sleeve rotatable in the air gap between the field andarmature poles. a generating winding. and means for altering the circuitof the generating winding at the irregular intervals determined by theficld and armature interpolar spaces.

1:). In a magneto for producing ignition currents at irregularintervals. a bipolar field magnet having intcrpolar spaces each lessthan 90. a bipolar armature having interpolar spaces each grcatcr than5H). a mag netic sleeve rotatable in the air gap be tween the field andarmature polcs and hav' ing two magnetic members each of a spansubstantially equal to the field inlcrpolar space. a generating winding.and means for alterv g the circuit of the generating wind ing at theirregular intervals determined b v the interpolar spaces of the fieldand aruuc ture.

10. In a magneto for producing ignition currents at irregular intervals.an llll1-. \llimetrical magnetic circuit. a generating winding havingprimary and secondary turns, a magnetic slecvc rotatablc in an air gapof said magnetic circuit. a mechanical interrupter for opening theclcclriczil circuit of the primary turns at thc irregular iiitervalsdetermined l1 v tbc llllt \'liilill'll'il'ill magnetic circuit. and adistributcr having a brush connected to one terminal of the secondar vturns and also having stationary sparlcplug distributing contactsarranged at angular intervals coricsponding with the irregular intervalsof operation of the incclzanical interrupter.

ln teslimon whcrcof l allix iuvsignaturc.

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